The diagnosis of nipple discharge will be determined upon an examination by a health provider who will ask questions about symptoms and medical history. Tests that may be done include:

- Prolactin blood test

- Thyroid blood tests

- Head CT scan or MRI to look for pituitary tumor

- Mammography

- Ultrasound of the breast

- Breast biopsy

- Ductography or ductogram: an x-ray with contrast dye injected into the affected milk duct

- Skin biopsy, if Paget disease is a concern

Individuals with inverted nipples may find that their nipples protract (come out) temporarily or permanently during pregnancy, or as a result of breastfeeding. Most women with inverted nipples who give birth are able to breastfeed without complication, but inexperienced mothers may experience higher than average pain and soreness when initially attempting to breastfeed. When a mother uses proper breastfeeding technique, the infant latches onto the areola, not the nipple, so women with inverted nipples are actually able to breastfeed without any problem. An infant that latches on well may be able to slush out an inverted nipple. The use of a breast pump or other suction device immediately before a feeding may help to draw out inverted nipples. A hospital grade electric pump may be used for this purpose. Some women also find that using a nipple shield can help facilitate breastfeeding. Frequent stimulation such as sexual intercourse and foreplay (such as nipple sucking) also helps the nipple protract.

Most of the time, nipple problems are not breast cancer. These problems will either go away with the right treatment, or they can be watched closely over time.

Another method of protracting inverted nipples is to have the nipple pierced. This method will only be effective if the nipple can be temporarily protracted. If pierced when protracted, the jewellery may prevent the nipple from returning to its inverted state. The success of both of these methods, from a cosmetic standpoint, is mixed. The piercing may actually correct the overly taut connective tissue to allow the nipple to become detached from underlying connective tissue and resume a more typical appearance.

The nipples of nursing mothers naturally make a lubricant to prevent drying, cracking, or infections. Cracked nipples may be able to be prevented by:

- Avoid soaps and harsh washing or drying of the breasts and nipples. This can cause dryness and cracking.

- Rubbing a little breast milk on the nipple after feeding to protect it.

- Keeping the nipples dry to prevent cracking and infection.

Roman chamomile can be applied directly to the skin for pain and swelling and is used to treat cracked nipples.

Multiple imaging modalities may be necessary to evaluate abnormalities of the nipple-areolar complex.

In two studies performed in Japan, high-resolution MRI with a microscopy coil yielding 0.137-mm in-plane resolution has been used to confirm the presence of abscesses, isolated fistulas and inflammation and to reveal their position in order to guide surgery.

Cracked nipples can be treated with 100% lanolin. Glycerin nipple pads can be chilled and placed over the nipples to help soothe and heal cracked or painful nipples. If the cause of cracked nipples is from thrush, treatment is usually begun with nystatin. If the mother is symptomatic then the mother and the baby can be treated. Continuing to breastfeed will actually help the nipples heal. A little breast milk or purified lanolin cream or ointment helps the healing process. Breastfeeding professionals that include nurses, midwives and lactation consultants are able to assist in the treatment of cracked nipples.

Advice from others is abundant but there have been some treatments that have been identified as not being effective in healing or preventing cracked nipples. These ineffective treatments are keeping the breastfeeding short and using a nipple guard. Keeping the feedings short so that the nipples can rest is not effective in relieving the pain of cracked nipples and it could have a negative effect on the milk supply. Nipple shields do not improve latching on.

The mother must remove the breast milk. If the baby can attach well and suckle, then she should breastfeed as frequently as the baby is willing. If the baby is not able to attach and suckle effectively, she should express her milk by hand or with a pump a few times until the breasts are softer, so that the baby can attach better, and then get them to breastfeed frequently.

She can apply warm compresses to the breast or take a warm shower before expressing, which helps the milk to flow. She can use cold compresses after feeding or expressing, which helps to reduce the oedema.

Engorgement occurs less often in baby-friendly hospitals which practise the Ten Steps and which help mothers to start breastfeeding soon after delivery.

Regular breastfeeding can be continued. The treatment for breast engorgement can be divided into non-medical and medical methods. The non-medical methods include hot/cold packs, Gua-Sha (scraping therapy), acupuncture and cabbage leaves whereas medical methods are proteolytic enzymes such as serrapeptase, protease, and subcutaneous oxytocin. Evidence from published clinical trials on the effectiveness of treatment options is of weak quality and is not strong enough to justify a clinical recommendation.

Failure to remove breast milk, especially in the first few days after delivery when the milk comes in and fills the breast, and at the same time blood flow to the breasts increases, causing congestion. The common reasons why milk is not removed adequately are delayed initiation of breastfeeding, infrequent feeds, poor attachment, ineffective suckling., a sudden change in breastfeeding routine, suddenly stopping breastfeeding, or if your baby suddenly starts breastfeeding less than usual.

In some cases, the accessory breast may not be visible at the surface. In these cases, it may be possible to distinguish their appearance from normal breast tissue with MRI. In other cases, accessory breasts have been known to lactate, as illustrated in a woodcut showing a child nursing at ectopic breast tissue on the lateral thigh.

There is some evidence that the condition may be more common in Native American populations.

The clinical management of a cyst of Montgomery depends upon the symptoms of the patient.

If there are no signs of infection, a cyst of Montgomery can be observed, because more than 80% resolve spontaneously, over only a few months. However, in some cases, spontaneous resolution may take up two years. In such cases, a repeat ultrasonography may become necessary. If, however, the patient has signs of an infection, for example reddening (erythema), warmth, pain and tenderness, a treatment for mastitis can be initiated, which may include antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs). With treatment, inflammatory changes usually disappear quickly. In rare cases, drainage may become necessary. A surgical treatment of a cyst of Montgomery, i.e. a resection, may become necessary only if a cyst of Montgomery persists, or the diagnosis is questioned clinically.

The prognosis seems to be excellent. In one series, all adolescent patients with a cyst of Montgomery had a favourable outcome.

The condition is usually self-limiting, and thus not indicated for surgery.

Breast eczema (also known as "Nipple eczema") may affect the nipples, areolae, or surrounding skin, with eczema of the nipples being of the moist type with oozing and crusting, in which painful fissuring is frequently seen, especially in nursing mothers. It will often occur in pregnancy even without breast feeding.

Persisting eczema of the nipple in the middle-aged and elderly needs to be discussed with a doctor, as a rare type of breast cancer called Paget's disease can cause these symptoms.

Treatment is problematic unless an underlying endocrine disorder can be successfully diagnosed and treated.

A study by Goepel and Panhke provided indications that the inflammation should be controlled by bromocriptine even in absence of hyperprolactinemia.

Antibiotic treatment is given in case of acute inflammation. However, this alone is rarely effective, and the treatment of a subareaolar abscess is primarily surgical. In case of an acute abscess, incision and drainage are performed, followed by antibiotics treatment. However, in contrast to peripheral breast abscess which often resolves after antibiotics and incision and drainage, subareaolar breast abscess has a tendency to recur, often accompanied by the formation of fistulas leading from inflammation area to the skin surface. In many cases, in particular in patients with recurrent subareolar abscess, the excision of the affected lactiferous ducts is indicated, together with the excision of any chronic abscess or fistula. This can be performed using radial or circumareolar incision.

There is no universal agreement on what should be the standard way of treating the condition. In a recent review article, antibiotics treatment, ultrasound evaluation and, if fluid is present, ultrasound-guided fine needle aspiration of the abscess with an 18 gauge needle, under saline lavage until clear, has been suggested as initial line of treatment for breast abscess in puerperal and non-puerperal cases including central (subareolar) abscess (see breast abscess for details). Elsewhere, it has been stated that treatment of subareolar abscess is unlikely to work if it does not address the ducts as such.

Duct resection has been traditionally used to treat the condition; the original Hadfield procedure has been improved many times but long term success rate remains poor even for radical surgery. Petersen even suggests that damage caused by previous surgery is a frequent cause of subareolar abscesses. Goepel and Pahnke and other authors recommend performing surgeries only with concomitant bromocriptine treatment.

The term "duct ectasia syndrome" has been used to describe symptoms of nonpuerperal mastitis, possibly associated with nipple inversion and nipple discharge. In some contexts, it was used to describe a particular form of nonpuerperal mastitis coincident with fibrocystic disease, frequently involving pasty (coloured) nipple discharge, nipple retraction, retroareolar abscess and blue dome cysts. Abscessation is not very frequent but by some definitions recurrent subareolar abscess is merely a variant of duct ectasia syndrome - abscessation would be obviously more frequent with this definition.

Duct ectasia syndrome has been associated with histopathological findings that are distinct from a simple duct widening. In addition to nonspecific duct widening the myoepithelial cell layer is atrophic, missing or replaced by fibrous tissue. The original cuboidal epithelial layer may be also severely impaired or missing. Characteristic calcifications are often visible on mammographic images.

Periductal mastitis, comedo mastitis, secretory disease of the breast, plasma cell mastitis and mastitis obliterans are sometimes considered special cases or synonyms of duct ectasia syndrome.

A supernumerary nipple (also known as a third nipple, triple nipple, accessory nipple, polythelia or the related condition: polymastia) is an additional nipple occurring in mammals, including humans. Often mistaken for moles, supernumerary nipples are diagnosed in humans at a rate of approximately 1 in 18 people.

The nipples appear along the two vertical "milk lines," which start in the armpit on each side, run down through the typical nipples and end at the groin. They are classified into eight levels of completeness from a simple patch of hair to a milk-bearing breast in miniature.

"Polythelia" refers to the presence of an additional nipple alone while "polymastia" denotes the much rarer presence of additional mammary glands.

Although usually presenting on the milk line, pseudomamma can appear as far away as the foot.

A possible relationship with mitral valve prolapse has been proposed.

A cyst of Montgomery may be asymptomatic. Yet, a cyst of Montgomery usually is diagnosed when a female patient, 10–20 years of age, complains to a healthcare professional of breast pain (mastalgia), inflammation or a palpable nodule in the breast. The diagnosis is made clinically, when a palpable nodule is felt in the retroareolar area.

The diagnosis can be confirmed with ultrasonography, frequently showing a simple cyst in the retroareolar area. In some patients, multiple cysts or bilateral cysts may exist. Cysts of Montgomery may have liquid content with an echogenic or calcific sediment.

Two small studies provide some indication that wearing a bra may have an overall negative effect on sagging breasts. In a Japanese study, 11 women were measured wearing a standardised fitted bra for three months. They found that breasts became larger and lower, with the underbust measurement decreasing and the overbust increasing, while the lowest point of the breast moved downwards and outwards. The effect was more pronounced in larger-breasted women. This may be related to the particular bra chosen for the experiment, as there was some improvement after changing to a different model.

A nipple bleb is a blister on the nipple that can be filled with serous fluid or another fluid. It may be pink or light yellow colour. It is thin-walled and may appear as a small blister. It is defined as being more than 5 mm in diameter. It can also be referred to as a bulla. Some clinicians may also include milk blisters as a type of bleb. In addition, a blocked Montgomery glad may also be called a nipple bleb though its cause is different than a milk or serous-filled bleb on the nipple. In some cased the bleb may be associated with an adjacent blocked sebaceous cyst.

Its cause may be due to a blocked pore that leads to seepage of milk or serous fluid under the epidermis. This causes a white 'bump' that appears opaque and shiny. If the bleb continues to block the flow of milk out of the breast it may develop into a blocked milk duct or even mastitis.

A nipple bleb is often treated by the woman herself since a warm saline soak and gentle washing may open the blister and cause it to drain.

Accessory breasts, also known as polymastia, supernumerary breasts, or mammae erraticae, is the condition of having an additional breast. Extra breasts may appear with or without nipples or areolae. It is a condition and a form of atavism which is most prevalent in male humans, and often goes untreated as it is mostly harmless. In recent years, many affected women have had a plastic surgery operation to remove the additional breasts, for purely aesthetic reasons.

A related condition, in which extra nipples form, is called "supernumerary nipple" or "polythelia".

Some women with ptosis choose to undergo plastic surgery to make their breasts less ptotic. Plastic surgeons offer several procedures for lifting sagging breasts. Surgery to correct the size, contour, and elevation of sagging breasts is called mastopexy. Women can also choose breast implants, or may undergo both procedures. The breast-lift procedure surgically elevates the parenchymal tissue (breast mass), cuts and re-sizes the skin envelope, and transposes the nipple-areola complex higher upon the breast hemisphere. If sagging is present and the woman opts not to undergo mastopexy, implants are typically placed above the muscle, to fill out the breast skin and tissue. Submuscular placement can result in deformity. In these cases, the implant appears to be high on the chest, while the natural breast tissue hangs down over the implant.

Recommended tests are a mammogram and a biopsy to confirm the diagnosis, and cytopathology may also be helpful. Paget's disease is difficult to diagnose due to its resemblance to dermatitis and eczema; even in patients after ductal carcinoma in situ surgery. Eczema tends to affect the areola first, and then the nipple, whereas Paget's spreads from the nipple.

During a physical examination, the doctor examines the unusual areas of the breast, especially the appearance of the skin on and around the nipples and feeling for any lumps or areas of thickening.

The most common test used to diagnose Paget's disease is the biopsy, removal of a tissue sample from the affected area which is then examined under the microscope by a pathologist, who distinguishes Paget cells from other cell types by staining tissues to identify specific cells (immunohistochemistry). Samples of nipple discharge may also be examined under the microscope to determine whether Paget cells are present.

Imprint or scrape cytopathology may be useful: scraping cells from the affected area, or pressing them onto a glass slide to be examined under the microscope.

On average, a woman may experience signs and symptoms for six to eight months before a diagnosis is made.

Fissure of the nipple is a condition that can be caused by friction that can result in soreness, dryness or irritation to, or bleeding of, one or both nipples during breastfeeding. It can also be the result of the friction of clothing against the nipple during physical exercise. This condition is also experienced by women who breastfeed and by surfers who do not wear rash guards.

The appearance of tuberous breasts can potentially be changed through surgical procedures, including the tissue expansion method and breast implants.

The procedure to change the appearance of tuberous breasts can be more complicated than a regular breast augmentation, and some plastic surgeons have specialist training in tuberous breast correction. As tuberous breasts are a congenital deformity, referral for treatment under the National Health Service may be possible in the United Kingdom. A starting point for those seeking such a referral may be a visit to their local General Practitioner. For those seeking non-surgical solutions, counseling may be recommended as a way of coming to terms with body image.

Ruling out the other possible causes of the pain is one way to differentiate the source of the pain. Breast pain can be due to:

- angina pectoris

- anxiety and depression

- bra

- blocked milk duct

- breastfeeding

- chest wall muscle pain

- consensual, rough sex

- costal chondritis (sore ribs)

- cutaneous candida infection

- duct ectasia (often with nipple discharge)

- engorgement

- fibroadenoma

- fibrocystic breast changes

- fibromyalgia

- gastroesophageal reflux disease

- herpes infection

- hormone replacement therapy

- mastalgia

- mastitis or breast infection

- menopause

- menstruation and Premenstrual syndrome

- perimenopause

- neuralgia

- pregnancy

- physical abuse

- pituitary tumor (often with nipple discharge)

- puberty in both girls and boys

- sexual abuse

- shingles

- sore nipples and cracked nipples

- surgery or biopsy

- trauma (including falls)

Medications can be associated with breast pain and include:

- Oxymetholone

- Chlorpromazine

- Water pills (diuretics)

- Digitalis preparations

- Methyldopa

- Spironolactone

Diagnostic testing can be useful. Typical tests used are mammogram, excisional biopsy for solid lumps, fine-needle aspiration and biopsy, pregnancy test, ultrasonography, and magnetic resonance imaging (MRI).